Methods and systems for the three-phase synthesis of carbonates from epoxides and carbon dioxide

Abstract

This invention relates to the field of catalyst technology, specifically to a method and system for synthesizing carbonates using a three-phase process of epoxides and carbon dioxide. The invention involves reacting liquid-phase epoxides and gaseous carbon dioxide with a solid-phase resin catalyst to obtain a reacted material. After stopping the reaction at any time, the reacted material is washed with a washing solvent until the epoxide concentration is <1 wt% and the carbonate concentration is <5 wt%. The washing solvent is then removed from the liquid-sealed resin catalyst through solid-liquid separation. Under heating conditions and a carbon dioxide atmosphere, the washing solvent entrained in the resin catalyst is purged and replaced to obtain a solid resin catalyst. This invention effectively achieves synthesis, recovery, and storage within a single reactor. Without the storage method for heterogeneous catalysts used in the synthesis of carbonates as described in this invention, the catalyst gradually breaks down, affecting its performance and causing loss, leading to increased bed resistance.

Description

Technical Field

[0001] This invention relates to the field of catalyst preservation technology, and specifically to a method and system for synthesizing carbonates using a three-phase method of epoxides and carbon dioxide. Background Technology

[0002] Lithium-ion battery electrolyte is an important component of the lithium battery industry chain, accounting for about 12% of the cost of lithium batteries. Lithium-ion battery electrolyte is generally composed of lithium salt, solvent and additives. The proportion of lithium salt is generally about 8%, solvent is 80-90%, and additives are 5-10%. The specific proportion will depend on the needs of downstream customers. The solvents currently mainly consist of five carbonate products: dimethyl carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate and ethylene carbonate.

[0003] Currently, the main industrialized methods for synthesizing carbonates both domestically and internationally are the ethylene oxide and carbon dioxide synthesis method, the phosgene method, the ethylene and carbon dioxide synthesis method, and the haloalcohol method. The phosgene method was the earliest method for preparing carbonates, but it has been phased out due to its long process flow, low yield of the target product, and the presence of polluting organochlorides. The ethylene and carbon dioxide synthesis method requires high pressure, posing an explosion hazard and making it difficult to industrialize. The haloalcohol method requires high temperatures, at which carbonates decompose, and due to its high raw material consumption and numerous byproducts, it has not been industrialized.

[0004] The synthesis of epoxides and carbon dioxide can utilize heterogeneous catalysts, such as resin catalysts. This approach reduces the need for subsequent product-catalyst separation, effectively decreasing energy consumption and investment. Furthermore, the resulting carbonates exhibit high purity and good industrial applicability. However, during plant-wide maintenance shutdowns or steam outages, and when the catalyst is still within its service life, storage becomes challenging. Due to the inherent properties of heterogeneous catalysts, their optimal temperature tolerance range is 50-150℃, while the freezing point of the product carbonates is <40℃. Low temperatures can cause the adsorbed carbonates in the resin catalyst to solidify and crystallize, leading to catalyst cracking. High temperatures, on the other hand, negatively impact catalyst activity. Therefore, the storage methods for heterogeneous resin catalysts require specific considerations compared to homogeneous catalysts. Summary of the Invention

[0005] The purpose of this invention is to solve the problem of catalyst storage difficulties during temporary shutdowns or steam outages in existing carbonate production plants when the catalyst has not yet reached its service life. The invention provides a method and system for synthesizing carbonates using a three-phase method of epoxides and carbon dioxide, which can be applied to the industrial production of carbonates. This method has the advantages of low cost, minimal impact on catalyst activity, and environmental friendliness.

[0006] According to a first aspect of the present invention, the present invention provides a method for synthesizing carbonates using a three-phase method of epoxides and carbon dioxide, the method comprising: contacting liquid-phase epoxides and gaseous carbon dioxide with a solid-phase resin catalyst to obtain a contacted material; after stopping the contact at any time period, the method further comprising:

[0007] (1) The material after contact is washed with a washing solvent until the concentration of alkyl epoxide is <1 wt% and the concentration of carbonate is <5 wt% to obtain a resin catalyst sealed with washing solvent.

[0008] (2) Optionally, the method further includes: solid-liquid separation of the washing solvent in the liquid-sealed resin catalyst, purging and replacing the washing solvent entrained in the resin catalyst under heating conditions, in an inert atmosphere and / or a carbon dioxide atmosphere to obtain a solid resin catalyst, and the heated purging tail gas.

[0009] According to a second aspect of the present invention, the present invention provides a system for synthesizing carbonates via a three-phase method using epoxides and carbon dioxide, the system comprising:

[0010] A three-phase synthesis reactor is used to react liquid-phase epoxy alkanes and gaseous carbon dioxide with a solid-phase resin catalyst bed to obtain the reacted material.

[0011] The liquid-phase epoxy alkane feed line and the gaseous carbon dioxide feed line are respectively used to supply liquid-phase epoxy alkane and gaseous carbon dioxide to the three-phase synthesis reactor.

[0012] A washing solvent feed line is used to supply washing solvent to the three-phase synthesis reactor after the contact is stopped at any time period, so as to wash the material after the contact with the washing solvent until the concentration of alkyl epoxide is <1 wt% and the concentration of carbonate is <5 wt%, to obtain a resin catalyst sealed with washing solvent.

[0013] A heat exchange unit is used to provide the required temperature for the three-phase synthesis reactor as needed.

[0014] The three-phase synthesis reactor includes a liquid phase inlet, a liquid phase outlet, a gas phase inlet, and a gas phase outlet;

[0015] Optionally, it also includes: a condenser and / or a heater disposed on the liquid phase discharge line and / or the gas phase discharge line.

[0016] This invention also provides a method for synthesizing carbonates using a three-phase process of epoxides and carbon dioxide. Liquid-phase epoxides and gaseous carbon dioxide react with a solid-phase resin catalyst in a three-phase synthesis reactor to obtain the reacted material. After stopping the reaction at any time interval, the method includes the following steps:

[0017] a) The washing solvent enters the three-phase synthesis reactor through the liquid inlet, and the jacket and / or external circulation heat exchanger are turned on for heating. The washing solvent washes the solid resin catalyst at a washing temperature above 40°C to obtain a circulating liquid containing the washing solvent and the contacted material.

[0018] b) Switch the external circulation heat exchanger to cooling function, turn on the circulation pump, and cool the circulating liquid in step a). Part of the liquid is collected as a reaction product through the reaction product collection channel, and the other part is circulated back to the liquid phase inlet and enters the three-phase synthesis reactor together with the newly added washing solvent to continue washing the solid resin catalyst. After multiple cycles of circulating and washing, close the jacket and / or the external circulation heat exchanger to obtain the resin catalyst sealed with washing solvent.

[0019] c) After cooling to room temperature, open the discharge port at the bottom of the catalyst bed section to discharge the resin catalyst sealed with washing solvent and the washing solvent together into a barrel for storage at room temperature.

[0020] d) Optionally, the washing solvent in the liquid-sealed resin catalyst is discharged through solid-liquid separation, the CO2 heater is turned on, and CO2 is introduced from the gas phase inlet at the bottom of the three-phase synthesis reactor. The heated CO2 is then used to purge and replace the washing solvent entrained in the resin catalyst from bottom to top. After purging for a period of time, a solid resin catalyst and heated purge tail gas are obtained.

[0021] e) Turn on the gas condenser on the gas phase discharge pipeline to condense and recover the washing solvent entrained in the heated purge tail gas in step c).

[0022] f) Turn off the CO2 heater and gas condenser, cool to room temperature, and store the solid resin catalyst from step c) directly in the three-phase synthesis reactor or open the discharge port at the bottom of the catalyst bed to discharge it into a barrel.

[0023] Current technologies for synthesizing carbonates are all homogeneous processes, using liquid catalysts. During maintenance, the materials and liquid catalysts in the reactor are directly discharged and treated as hazardous waste, which is both wasteful and environmentally unfriendly. No existing technology addresses the treatment of catalysts in three-phase synthesis methods. This invention solves the problem of catalyst storage difficulties during temporary shutdowns or steam outages in carbonate production plants, especially when the catalyst is still within its service life. It offers advantages such as low cost, minimal impact on catalyst activity, environmental friendliness, and practicality.

[0024] This invention can effectively achieve synthesis, recovery, and storage in a single reactor. If the heterogeneous catalyst for synthesizing carbonates is not stored using the method of this invention, the temperature of the reactor will gradually decrease in the absence of steam and other heat sources. When the temperature drops below 45°C, the catalyst will gradually break down, affecting its performance and causing loss, and increasing the bed resistance drop. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of a system flow diagram for the three-phase synthesis of carbonates from epoxides and carbon dioxide according to a preferred embodiment of the present invention;

[0026] Figure 2 This is a schematic diagram of the structure of a three-phase synthesis reactor according to a preferred embodiment of the present invention.

[0027] Figure Labels

[0028] I is a three-phase synthesis reactor; II is a CO2 heater; III is a gas condenser; IV is an external circulation heat exchanger; V is a circulation pump;

[0029] 3 is the extraction channel; 10 is the liquid distributor; 11 is the upper wire mesh; 12 is the loading port; 13 is the catalyst bed section; 14 is the jacket; 15 is the unloading port; 16 is the lower wire mesh; 17 is the gas distributor. Detailed Implementation

[0030] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0031] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0032] In this invention, unless otherwise stated, directional terms such as "upper," "lower," "left," and "right" generally refer to the upper, lower, left, and right as shown in the accompanying drawings; "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0033] The first aspect of this invention provides a method for synthesizing carbonates using a three-phase process of epoxides and carbon dioxide. The method includes: contacting liquid-phase epoxides and gaseous carbon dioxide with a solid-phase resin catalyst to obtain a reacted material; after stopping the contact at any time interval, the method further includes:

[0034] 1) The contacted material is washed with a washing solvent until the concentration of alkyl epoxides is <1 wt% and the concentration of carbonates is <5 wt%, to obtain a resin catalyst sealed with washing solvent;

[0035] 2) Optionally, the method further includes: solid-liquid separation of the washing solvent in the liquid-sealed resin catalyst, purging the washing solvent entrained in the resin catalyst under heating conditions, in an inert atmosphere and / or a carbon dioxide atmosphere to obtain a solid resin catalyst, and the heated purging tail gas.

[0036] Existing technologies are all homogeneous processes, where the catalyst is liquid, not solid. During plant-wide maintenance, the materials and catalyst in the reactor are typically unloaded together and treated as hazardous waste, which is both wasteful and environmentally unfriendly. This invention solves the problem of catalyst storage difficulties during temporary shutdowns or steam outages in carbonate production plants, especially when the catalyst has not yet reached its service life. It allows for catalyst recycling, offering advantages such as low cost, minimal impact on catalyst activity, environmental friendliness, and practicality.

[0037] According to a preferred embodiment of the present invention, the washing solvent in the resin catalyst discharged from the solid-liquid separation liquid seal is transported to an ethylene glycol unit or a dimethyl carbonate unit as a raw material, depending on the solvent.

[0038] According to a preferred embodiment of the present invention, the method further includes: condensing the heated purge exhaust gas to recover the washing solvent entrained in the purge exhaust gas.

[0039] According to a preferred embodiment of the present invention, in step 1), the contacted material is washed with a washing solvent until the concentration of alkyl epoxides is <0.5wt% and the concentration of carbonates is <1wt%.

[0040] According to a preferred embodiment of the present invention, the washing temperature is higher than 40°C, preferably 50-80°C.

[0041] According to a preferred embodiment of the present invention, the washing solvent is a solvent capable of dissolving the liquid-phase epoxide and carbonate and inert to the contact reaction. Preferably, the washing solvent is selected from one or more of water, methanol, ethylene glycol, diethylene glycol, propylene glycol, and polypropylene glycol. More preferably, the washing solvent is water and / or methanol.

[0042] Since solid resin catalysts are temperature-sensitive, they cannot be too high or too low. Too high a temperature will affect their activity, while too low a temperature will cause the residual material to crystallize, which will cause the catalyst to crack and be damaged. Therefore, according to the preferred embodiment of the present invention, in step 2), the heating condition is 60-150°C.

[0043] According to a preferred embodiment of the present invention, the solvent content in the purged resin catalyst is preferably less than 5% by weight.

[0044] According to a preferred embodiment of the present invention, the contact reaction has no special requirements, but the preferred conditions for the contact reaction include: a temperature of 80-150°C; and a molar ratio of gaseous carbon dioxide to liquid epoxide alkane of 1.01-2.

[0045] According to a preferred embodiment of the present invention, the amount of resin catalyst used is 0.5-5 times the ratio of liquid phase epoxide alkane feed.

[0046] In this invention, the resin catalyst can be selected from a wide range of types, such as one or more of polyalkylene esters, copolymers of styrene and divinylbenzene, polyesters, polycarbonates, polyurethanes or formaldehyde resins.

[0047] like Figure 1 As shown, the present invention provides a system for synthesizing carbonates via a three-phase method using epoxides and carbon dioxide, the system comprising:

[0048] Three-phase synthesis reactor I is used to react liquid-phase epoxy alkane and gaseous carbon dioxide with solid-phase resin catalyst bed 13 to obtain the contacted material.

[0049] The liquid-phase epoxy alkane feed line and the gaseous carbon dioxide feed line are respectively used to supply liquid-phase epoxy alkane and gaseous carbon dioxide to the three-phase synthesis reactor I.

[0050] A washing solvent feed line is used to supply washing solvent to the three-phase synthesis reactor I after the contact is stopped at any time period, so as to wash the material after the contact with the washing solvent until the concentration of alkyl epoxide is <1 wt% and the concentration of carbonate is <5 wt%, to obtain a resin catalyst sealed with washing solvent.

[0051] The heat exchange unit is used to provide the required temperature for the three-phase synthesis reactor I as needed;

[0052] The three-phase synthesis reactor I includes a liquid phase inlet, a liquid phase outlet, a gas phase inlet, and a gas phase outlet;

[0053] Optionally, it also includes: a gas condenser III and / or a heater disposed on the liquid phase discharge line and / or the gas phase discharge line.

[0054] According to a preferred embodiment of the present invention, the system includes: the gas condenser III is disposed on the gas phase outlet pipeline of the three-phase synthesis reactor I for cooling the outlet tail gas and recovering the washing solvent.

[0055] According to a preferred embodiment of the present invention, the heat exchange unit is an external circulation heat exchanger IV and / or a jacket 14 disposed in the catalyst bed section 13 of the three-phase synthesis reactor I.

[0056] According to a preferred embodiment of the present invention, the heat exchange unit preferably includes an external circulation heat exchanger IV and the jacket 14 disposed in the catalyst bed section 13 of the three-phase synthesis reactor I.

[0057] According to a preferred embodiment of the present invention, more preferably, the external circulation heat exchanger IV is connected to the circulation pump V, and the circulation pump V is connected to the liquid phase inlet of the three-phase synthesis reactor I.

[0058] According to a preferred embodiment of the present invention, a reaction product extraction channel 3 is provided on the circulating pump pipeline for extracting the reaction product.

[0059] According to a preferred embodiment of the present invention, the system further includes a CO2 heater II disposed on the gas phase carbon dioxide feed line.

[0060] According to a preferred embodiment of the present invention, the liquid phase inlet is disposed on the upper side wall of the three-phase synthesis reactor I, the gas phase inlet is disposed on the lower side wall of the three-phase synthesis reactor I, the liquid phase outlet is disposed on the bottom of the three-phase synthesis reactor I, and the gas phase outlet is disposed on the top of the three-phase synthesis reactor I.

[0061] like Figure 2 As shown, according to a preferred embodiment of the present invention, the three-phase synthesis reactor I mainly comprises, from top to bottom:

[0062] A liquid distributor 10 for dispersing the liquid phase, the liquid distributor 10 being connected to the liquid phase inlet;

[0063] The upper wire mesh 11 is used to intercept the catalyst when the gas is blown from bottom to top;

[0064] Catalyst bed section 13;

[0065] The lower wire mesh 16 is used to intercept the catalyst; and

[0066] A gas distributor 17 for dispersing the gas phase, the gas distributor 17 being connected to the gas phase inlet; and also including a loading port 12 and a discharge port 15 respectively disposed at the top and bottom of the catalyst bed section 13, and a jacket 14 disposed outside the catalyst bed section 13.

[0067] According to a preferred embodiment of the present invention, the volume of the three-phase synthesis reactor is preferably 10-15 m³. 3 3-5 tons of resin catalyst were loaded.

[0068] In this invention, various pipelines or valves, as well as components that may be used in industry, can be added to each part as needed. This invention has no special requirements in this regard.

[0069] like Figure 1-2As shown, the system process flow for synthesizing carbonates using the three-phase method of epoxy alkane and carbon dioxide in this invention is described below:

[0070] Liquid-phase epoxides and gaseous carbon dioxide react with a solid-phase resin catalyst to obtain the reacted material. After the contact is stopped at any time, the washing solvent is dispersed into the three-phase synthesis reactor through a liquid distributor at the top of the reactor, passing through the upper wire mesh and entering the catalyst bed to wash the solid-phase resin catalyst from top to bottom. The circulating liquid containing epoxides and carbonates after washing is cooled by an external circulation heat exchanger and then pressurized by a circulation pump. Part of it is recycled back to the liquid distributor at the top of the three-phase synthesis reactor to continue washing the solid-phase resin catalyst with the newly added washing solvent, while the other part is collected as a reaction product through the collection channel. This process of repeated washing and circulation can yield a resin catalyst sealed with washing solvent, suitable for long-term storage.

[0071] It is understood that the solid-phase resin catalyst of the present invention can also be stored in solid form; the washing solvent in the liquid-sealed resin catalyst is discharged through solid-liquid separation, and carbon dioxide passes through the CO2 heater, is distributed from the bottom gas distributor of the three-phase synthesis reactor, passes through the lower wire mesh and enters the catalyst bed, and the washing solvent entrained in the resin catalyst is purged and replaced to obtain the solid resin catalyst. The heated purging tail gas is condensed and recovered from the gas phase outlet at the top of the reactor through the condenser.

[0072] This invention can solve the problem of catalyst storage difficulties during temporary shutdowns or steam outages in carbonate production plants when the catalyst has not yet reached the end of its service life. It has the advantages of low cost, minimal impact on catalyst activity, environmental friendliness, and practicality.

[0073] like Figure 1 As shown, this invention provides a method for synthesizing carbonates using a three-phase process of epoxides and carbon dioxide. Liquid-phase epoxides and gaseous carbon dioxide react with a solid-phase resin catalyst in a three-phase synthesis reactor to obtain the reacted material. After stopping the reaction at any time interval, the method includes the following steps:

[0074] a) The washing solvent enters the three-phase synthesis reactor I through the liquid inlet, and the jacket 14 and / or the external circulation heat exchanger IV are turned on for heating. The washing solvent washes the solid resin catalyst at a washing temperature above 40°C to obtain a circulating liquid containing the washing solvent and the contacted material.

[0075] b) Switch the external circulation heat exchanger IV to cooling function, turn on the circulation pump V, and cool the circulating liquid in step a). Part of the liquid is collected as a reaction product through the collection channel 3, and the other part is circulated back to the liquid phase inlet and enters the three-phase synthesis reactor I together with the newly added washing solvent to continue washing the solid resin catalyst. After multiple cycles of circulation and washing, the resin catalyst sealed with washing solvent is obtained. Then, the jacket 14 and / or the external circulation heat exchanger IV are closed.

[0076] c) After cooling to room temperature, open the discharge port 15 at the bottom of the catalyst bed section 13 to discharge the resin catalyst sealed with washing solvent and the washing solvent together into a barrel for storage at room temperature.

[0077] d) Optionally, the washing solvent in the liquid-sealed resin catalyst is discharged through solid-liquid separation, CO2 heater II is turned on, and CO2 is introduced from the gas phase inlet at the bottom of the three-phase synthesis reactor I, so that the heated CO2 purges and replaces the washing solvent entrained in the resin catalyst from bottom to top. After purging for a period of time, a solid resin catalyst and heated purge tail gas are obtained.

[0078] e) Turn on the gas condenser III on the gas phase discharge pipeline to condense and recover the washing solvent entrained in the heated purge tail gas in step c).

[0079] f) Turn off CO2 heater II and gas condenser III, cool to room temperature, and store the solid resin catalyst from step c) directly in the three-phase synthesis reactor I or open the unloading port 15 at the bottom of the catalyst bed 13 to unload it into a barrel.

[0080] According to a preferred embodiment of the present invention, the number of cyclic washing cycles in step b) is 1-10 times, preferably 2-5 times.

[0081] According to a preferred embodiment of the present invention, the contacted material is washed with a washing solvent until the concentration of alkyl epoxides is <0.5 wt% and the concentration of carbonates is <1 wt%.

[0082] According to a preferred embodiment of the present invention, the washing temperature is 50-80°C.

[0083] According to a preferred embodiment of the present invention, the washing solvent is a solvent capable of dissolving the liquid-phase epoxide and carbonate and inert to the contact reaction. Preferably, the washing solvent is selected from one or more of water, methanol, ethylene glycol, diethylene glycol, propylene glycol, and polypropylene glycol. More preferably, the washing solvent is water and / or methanol.

[0084] According to a preferred embodiment of the present invention, the CO2 purging time in step d) is 6-24h, preferably 6-12h.

[0085] According to a preferred embodiment of the present invention, the operating conditions of the three-phase synthesis reactor include a temperature of 60-150°C.

[0086] According to a preferred embodiment of the present invention, the solvent content in the purged resin catalyst is less than 5% by weight.

[0087] According to a preferred embodiment of the present invention, the condensation temperature in step e) is 45-100°C, preferably 45-80°C, and more preferably 45-70°C.

[0088] According to a preferred embodiment of the present invention, the conditions for the contact reaction include:

[0089] The temperature is 80-150℃; the molar ratio of gaseous carbon dioxide to liquid epoxide is 1.01-2; and the feed ratio of resin catalyst to liquid epoxide is 0.5-5.

[0090] According to a preferred embodiment of the present invention, the resin catalyst is preferably one or more of polyalkylene ester, copolymer of styrene and divinylbenzene, polyester, polycarbonate, polyurethane or formaldehyde resin.

[0091] The present invention will be further illustrated below with reference to embodiments and comparative examples, but the apparatus and method of the present invention are not limited thereto.

[0092] The following embodiments employ the following methods: Figure 1 The system shown and as Figure 2 The three-phase synthesis reactor shown is used for the process, and the three-phase synthesis reactor includes:

[0093] The three-phase synthesis reactor I is arranged from top to bottom as follows: liquid distributor 10, upper wire mesh 11, catalyst bed 13, lower wire mesh 16, and gas distributor 17; jacket 14 located outside the catalyst bed 13; loading port 12 and unloading port 15 located at the top and bottom of the catalyst bed, respectively; liquid phase inlet and gas phase inlet located on the upper and lower side walls of the three-phase synthesis reactor I, respectively; liquid phase outlet and gas phase outlet located at the bottom and top of the three-phase synthesis reactor, respectively.

[0094] The system includes:

[0095] CO2 heater II, three-phase synthesis reactor I, external circulation heat exchanger IV, circulation pump V and gas condenser III;

[0096] The inlet of the CO2 heater II is connected to the CO2 supply pipeline, and its outlet is connected to the gas phase inlet of the three-phase synthesis reactor I. It enters the gas distributor 17, passes through the lower wire mesh 16 and enters the catalyst bed 13, where it purges and removes the washing solvent from the catalyst.

[0097] The gas phase outlet at the top of the three-phase synthesis reactor I is connected to the inlet of the gas condenser III, and the outlet of the gas condenser III is connected to the subsequent system for condensing and recovering the washing solvent in the purge gas.

[0098] The inlet of the external circulation heat exchanger IV is connected to the liquid phase outlet of the three-phase synthesis reactor I, and is used to cool or heat the reaction system with the washing solvent. The outlet of the external circulation heat exchanger IV is connected to the inlet of the circulation pump V.

[0099] The outlet of the circulating pump V is connected to the liquid inlet at the top of the three-phase synthesis reactor I, and the liquid inlet is also connected to the washing solvent feed pipeline, so that the circulating liquid and the newly added washing solvent enter the catalyst bed through the liquid distributor 10, and the catalyst is repeatedly washed. The pipeline is also provided with a collection channel 3 for collecting the reaction products, which is used to discharge the reaction products in the circulating liquid.

[0100] The conditions for the reaction of liquid-phase epoxides and gaseous carbon dioxide with solid-phase resin catalysts include:

[0101] The temperature is 80-150℃; the molar ratio of gaseous carbon dioxide to liquid epoxides is 1.01-2;

[0102] The ratio of resin catalyst to liquid-phase epoxide alkane feed is 0.5-5;

[0103] The resin catalyst is preferably one or more of polyalkylene esters, copolymers of styrene and divinylbenzene, polyesters, polycarbonates, polyurethanes, or formaldehyde resins.

[0104] After the contact reaction is complete, the following steps are included:

[0105] 1) Add washing solvent to the three-phase synthesis reactor I, turn on jacket 14 and / or external circulation heat exchanger IV, use hot water or steam to heat, and keep the temperature of the reaction system >40°C;

[0106] 2) Start the circulation pump V and circulate the washing solution multiple times until the carbonate content in the system is <5%;

[0107] 3) Introduce CO2 and turn on the CO2 heater II to heat to 60-150℃;

[0108] 4) Open the gas condenser III connected to the top of the reactor to condense and recover the washing solvent in the purge gas;

[0109] 5) Continuously purge until the moisture content of the solid resin catalyst is <5%, then turn off the CO2 heater;

[0110] 6) After the catalyst is cooled to room temperature, it is discharged from the discharge port 15 and placed in a barrel or stored directly in the reactor;

[0111] 7) The washing solvent is delivered to the ethylene glycol unit or the dimethyl carbonate unit as a raw material.

[0112] Example 1

[0113] Steam was temporarily shut down due to unit maintenance; the solid-phase resin catalyst had not yet reached its service life. The reactor volume is 15m³. 3 The following is the specific operating procedure before shutting down steam: 5 tons of solid resin catalyst are loaded.

[0114] 1) Add water to the three-phase synthesis reactor I, open the jacket 14 or the external circulation heat exchanger III, and use hot water or steam to heat the system and maintain the temperature of the reaction system at 50°C.

[0115] 2) Start the circulation pump V and circulate and wash 4 times until the carbonate content in the system is 3wt%;

[0116] 3) Introduce CO2 and turn on CO2 heater II to heat to 130℃;

[0117] 4) Turn on the gas condenser III at the top of the reactor and condense it to 50°C to condense and recover the solvent in the tail gas;

[0118] 5) Purge continuously for 12 hours until the content of solvent in the solid resin catalyst is 1 wt%, then turn off the CO2 heater.

[0119] 6) After the solid-phase resin catalyst is cooled to room temperature, it is unloaded and placed in a barrel or stored directly in the three-phase synthesis reactor.

[0120] 7) The washing liquid containing water and carbonates is fed to the ethylene glycol unit as a feedstock.

[0121] Example 2

[0122] Steam was temporarily shut down due to unit maintenance; the solid-phase resin catalyst had not yet reached its service life. The reactor volume is 15m³. 3 The following is the specific operating procedure before shutting down steam: 5 tons of solid resin catalyst are loaded.

[0123] 1) Add methanol to the three-phase synthesis reactor I, open the jacket 14 or the external circulation heat exchanger III, and use hot water or steam to heat the system and maintain the temperature of the reaction system at 45°C.

[0124] 2) Start the circulation pump V and circulate the wash 3 times until the carbonate content in the system reaches 4wt%;

[0125] 3) Introduce CO2 and turn on CO2 heater II to heat to 80°C;

[0126] 4) Turn on the top gas condenser III of the three-phase synthesis reactor and condense it to 45°C to recover the solvent in the tail gas.

[0127] 5) Purge continuously for 8 hours until the water content of the solid resin catalyst is 4wt%, then turn off the CO2 heater;

[0128] 6) After the solid-phase resin catalyst is cooled to room temperature, it is unloaded and placed in a barrel or stored directly in the three-phase synthesis reactor.

[0129] 7) The washing liquid containing methanol and carbonate is fed to the dimethyl carbonate unit as a feedstock.

[0130] Example 3

[0131] Steam was temporarily shut down due to unit maintenance; the catalyst had not yet reached its service life. The reactor volume is 10m³. 3 Three tons of solid resin catalyst were loaded, and the specific operation method is as follows:

[0132] Add ethylene glycol to the three-phase synthesis reactor I, open the jacket 14 or the external circulation heat exchanger III, and use hot water or steam to heat the system and maintain the temperature of the reaction system at 80°C.

[0133] Start circulation pump V and circulate the wash 5 times until the carbonate content in the system reaches 2wt%.

[0134] Close jacket 14 or external circulation heat exchanger III, and after cooling to room temperature, unload the catalyst and solvent together from the catalyst discharge port and store them in drums at room temperature.

[0135] The next time you start the engine, replace the carbonate with carbonate and then proceed to the subsequent carbonate distillation system or dimethyl carbonate unit.

[0136] Example 4

[0137] The unit was temporarily shut down for maintenance, but steam supply was not interrupted. The solid-phase resin catalyst had not yet reached its service life. The reactor volume is 10m³. 3 Three tons of solid resin catalyst were loaded, and the specific operation method is as follows:

[0138] Open jacket 14 or external circulation heat exchanger III, and use hot water or steam to heat the reaction system and maintain the temperature of the reaction system >40℃;

[0139] Maintain the reaction temperature above 40°C until the next restart.

[0140] As can be seen from the above, the present invention can effectively realize synthesis-recovery-storage in one reactor. If the heterogeneous catalyst for synthesizing carbonates of the present invention is not used, the temperature of the reactor will gradually decrease in the absence of steam and other heat sources. When it is below 45°C, the catalyst will gradually break down, affecting the catalyst performance and causing loss, and the bed resistance drop will increase.

[0141] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for synthesizing carbonates via a three-phase process using epoxides and carbon dioxide, characterized in that, The method includes: reacting liquid-phase epoxides and gaseous carbon dioxide with a solid-phase resin catalyst to obtain the reacted material; after stopping the contact at any time period, the method further includes: 1) The contacted material is washed with a washing solvent until the concentration of alkyl epoxides is <1 wt% and the concentration of carbonates is <5 wt%, to obtain a resin catalyst sealed with washing solvent; 2) Optionally, the method further includes: solid-liquid separation of the washing solvent in the liquid-sealed resin catalyst, purging the washing solvent entrained in the resin catalyst under heating conditions, in an inert atmosphere and / or a carbon dioxide atmosphere to obtain a solid resin catalyst, and the heated purging tail gas.

2. The method according to claim 1, further comprising: The heated purge exhaust gas is condensed to recover the washing solvent entrained in the purge exhaust gas.

3. The method according to claim 1, wherein, In step 1), The material after contact is washed with a washing solvent until the concentration of alkyl epoxides is <0.5 wt% and the concentration of carbonates is <1 wt%. and / or The washing temperature is above 40°C, and / or The washing solvent is a solvent capable of dissolving the liquid-phase epoxides and carbonates and inert to the contact reaction.

4. The method according to claim 3, wherein, In step 1), The washing temperature is 50-80℃; and / or The washing solvent is selected from one or more of water, methanol, ethylene glycol, diethylene glycol, propylene glycol, and polypropylene glycol.

5. The method according to claim 4, wherein, In step 1), The washing solvent is water and / or methanol.

6. The method according to claim 1, wherein, In step 2), The heating conditions are 60-150℃; and / or After purging, the solvent content in the resin catalyst is less than 5% by weight.

7. The method according to claim 1, wherein, The conditions for the contact reaction include: The temperature is 80-150℃; the molar ratio of gaseous carbon dioxide to liquid epoxides is 1.01-2; The ratio of resin catalyst to liquid-phase epoxide alkane feed is 0.5-5; The resin catalyst is one or more of polyalkylene esters, copolymers of styrene and divinylbenzene, polyesters, polycarbonates, polyurethanes, or formaldehyde resins.

8. A system for synthesizing carbonates via a three-phase method using epoxides and carbon dioxide, characterized in that, The system includes: A three-phase synthesis reactor (I) is used to react liquid-phase epoxides and gaseous carbon dioxide with a solid-phase resin catalyst bed (13) to obtain the reacted material. The liquid-phase epoxy alkane feed line and the gaseous carbon dioxide feed line are respectively used to supply liquid-phase epoxy alkane and gaseous carbon dioxide to the three-phase synthesis reactor (I); A washing solvent feed line is used to supply washing solvent to the three-phase synthesis reactor (I) after the contact is stopped at any time period, so as to wash the material after the contact with washing solvent until the concentration of alkyl epoxide is <1 wt% and the concentration of carbonate is <5 wt%, to obtain a resin catalyst sealed with washing solvent. A heat exchange unit is used to provide the required temperature for the three-phase synthesis reactor (I) as needed; The three-phase synthesis reactor (I) includes a liquid phase inlet, a liquid phase outlet, a gas phase inlet, and a gas phase outlet; Optionally, it also includes: a condenser and / or a heater disposed on the liquid phase discharge line and / or the gas phase discharge line.

9. The system according to claim 8, wherein, The system includes a gas condenser (III), which is installed on the gas phase outlet pipeline of the three-phase synthesis reactor (I) for cooling the outlet tail gas and recovering the washing solvent.

10. The system according to claim 8, wherein, The heat exchange unit is an external circulation heat exchanger (IV) and / or a jacket (14) installed in the catalyst bed section (13) of the three-phase synthesis reactor (I).

11. The system according to claim 10, wherein, The heat exchange unit includes an external circulation heat exchanger (IV) and the jacket (14) disposed in the catalyst bed section (13) of the three-phase synthesis reactor (I).

12. The system according to claim 11, wherein, The external circulation heat exchanger (IV) is connected to the circulation pump (V), which is connected to the liquid phase inlet of the three-phase synthesis reactor (I).

13. The system according to claim 12, wherein, The circulating pump pipeline is provided with a reaction product extraction channel (3) for extracting the reaction product.

14. The system according to claim 8, wherein, The system also includes: a CO2 heater (II) disposed on the gas phase carbon dioxide feed line; and / or The liquid phase inlet is located on the upper side wall of the three-phase synthesis reactor (I), the gas phase inlet is located on the lower side wall of the three-phase synthesis reactor (I), the liquid phase outlet is located at the bottom of the three-phase synthesis reactor (I), and the gas phase outlet is located at the top of the three-phase synthesis reactor (I).

15. The system according to claim 8, wherein, The three-phase synthesis reactor (I) comprises, from top to bottom: A liquid distributor (10) for dispersing the liquid phase, the liquid distributor (10) being connected to the liquid phase inlet; The upper wire mesh (11) is used to intercept the catalyst when the gas is blown from bottom to top; Catalyst bed section (13); The lower wire mesh (16) used to intercept the catalyst; and A gas distributor (17) for dispersing the gas phase, the gas distributor (17) being connected to the gas phase inlet; It also includes a loading port (12) and a discharge port (15) respectively disposed at the top and bottom of the catalyst bed section (13), and a jacket (14) disposed outside the catalyst bed section (13).

16. A method for synthesizing carbonates via a three-phase process using epoxides and carbon dioxide, characterized in that, Liquid-phase epoxy alkane and gaseous carbon dioxide are reacted with a solid-phase resin catalyst in a three-phase synthesis reactor to obtain the reacted material. After the contact is stopped at any time period, the method includes the following steps: a) The washing solvent enters the three-phase synthesis reactor (I) through the liquid inlet, and the jacket (14) and / or the external circulation heat exchanger (IV) are turned on for heating. The washing solvent washes the solid resin catalyst at a washing temperature above 40°C to obtain a circulating liquid containing the washing solvent and the contacted material. b) Switch the external circulation heat exchanger (IV) to cooling function, turn on the circulation pump (V), and cool the circulating liquid in step a). Part of the liquid is collected as a reaction product through the collection channel (3), and the other part is circulated back to the liquid phase inlet and enters the three-phase synthesis reactor (I) together with the newly added washing solvent to continue washing the solid phase resin catalyst. After multiple cycles of circulating and washing, the resin catalyst sealed with washing solvent is obtained. Then, the jacket (14) and / or the external circulation heat exchanger (IV) are closed. c) After cooling to room temperature, open the discharge port (15) at the bottom of the catalyst bed section (13) to discharge the resin catalyst sealed with washing solvent and the washing solvent together into a barrel for storage at room temperature. d) Optionally, the washing solvent in the liquid-sealed resin catalyst is discharged through solid-liquid separation, and the CO2 heater (II) is turned on. CO2 is introduced from the gas phase inlet at the bottom of the three-phase synthesis reactor (I) so that the heated CO2 purges and replaces the washing solvent entrained in the resin catalyst from bottom to top. After purging for a period of time, a solid resin catalyst and heated purge tail gas are obtained. e) Turn on the gas condenser (III) on the gas phase discharge line to condense and recover the washing solvent entrained in the purge tail gas after heating in step c). f) Turn off the CO2 heater (II) and gas condenser (III), cool to room temperature, and store the solid resin catalyst from step c) directly in the three-phase synthesis reactor (I) or open the unloading port (15) at the bottom of the catalyst bed (13) to unload it into a barrel.

17. The method of use according to claim 16, wherein, In step b): The number of cycles is 1-10; and / or The material after contact is washed with a washing solvent until the concentration of alkyl epoxides is <0.5 wt% and the concentration of carbonates is <1 wt%. and / or The washing temperature is 50-80℃; and / or The washing solvent is a solvent capable of dissolving the liquid-phase epoxides and carbonates and inert to the contact reaction; and / or In step d): CO2 purging time is 6-24 hours; and / or The operating conditions for the three-phase synthesis reactor include: a temperature of 60-150℃; and / or After purging, the solvent content in the resin catalyst is less than 5% by weight; and / or The condensation temperature in step e) is 45-100℃; and / or The conditions for the contact reaction include: The temperature is 80-150℃; the molar ratio of gaseous carbon dioxide to liquid epoxides is 1.01-2; The ratio of resin catalyst to liquid-phase epoxide alkane feed is 0.5-5; The resin catalyst is one or more of polyalkylene esters, copolymers of styrene and divinylbenzene, polyesters, polycarbonates, polyurethanes, or formaldehyde resins.

18. The method of use according to claim 17, wherein, In step b): The number of wash cycles is 2-5; and / or The washing solvent is selected from one or more of water, methanol, ethylene glycol, diethylene glycol, propylene glycol, and polypropylene glycol; and / or In step d): CO2 purging time is 6-12 hours; and / or The condensation temperature in step e) is 45-80℃.

19. The method of use according to claim 18, wherein, The washing solvent is water and / or methanol; and / or The condensation temperature in step e) is 45-70℃.

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